The answer to your first question is “yes” only if you are dealing with a frame and wheel that is disc brake compatible. Rim brakes won’t work with such a change in diameter. Pretty simple there.

The second answer, “negatively”, is a bit more complicated. Let’s take a look at what really is going on when we pop a 26″er wheel in a 29″er frame. Think of the front axle as a pivoting point. Now imagine lowering the rear end of your bike without a rear wheel in it by pivoting the bike downwards around that front axle. Watch how the angles all become slacker and the bottom bracket gets a little closer to the ground. Yep! That’s what is going to happen to your 29 inch wheeled bike when you put a smaller rear wheel back there.

This causes several things, all of which I would deem negative, and I think most of the time, in most cases it is true. First the head angle gets shallower, causing slower steering and strange cornering behaviour. The seat angle changes, putting you further behind the bottom bracket and adversely affecting your seated pedaling posistion. It also will make seated to standing pedaling posistion maneuvers more difficult to pull off. Finally, your bottom bracket will be closer to the ground, increasing the chances for pedal strikes.

Now for the third answer, “not really”. It isn’t going to be a good representation of what a properly designed mixed wheel bike will do. At best, you will have a functional bicycle, at worst, it may be deemed unridable off road. Best to save up for a properly designed mixed wheel bike and leave the 29″er alone.

You might remember our Interbike Coverage from last fall when we showed you the first prototype of a new soft tail design by Siren Bicycles called “Song”. The first prototypes have been ridden and analysed and now Brendan Collier, head honch of Siren Bicycles, has developed some parts that have refined and improved upon the originals.

As you can see, the flex plate assembly mock up shown here has been refined and changed a lot from the original design. Brendan moved the flex plate brace to the underside, minimized the chainstay connection, and basically gave the whole assembly a cleaner more organic look over the original.

A bottom view of what the flex plate assembly will look like

Brendan has told me that developement is moving right along and that the next generation of Song bikes with the new flex plate should be debuting this spring. Actual Song bicycles for sale should follow shortly there after. The Song itself will be available in a “55” format, (Brendan’s moniker for a 69er design) or as a full on 29″er. Design features promise at least 1.5″ of rear travel using a Cane Creek damper unit. Tire clearance has been improved with the new flex plate, but until actual bikes hit the trails I can not report on how big a tire will fit yet.

The bolted assembly may allow for switching out of rear triangles or to allow for breaking down the bike for travel purposes. Two possible features that Brendan is looking at yet but may not make it to production.

Thanks go out to Brendan Collier and Siren Bicycles for sharing this update with Twenty Nine Inches. We will be bringing you more on the Song or any other Siren 29″ers as the news becomes available.

One of the highlights for me from the recently held Interbike trade show was catching up with Brendan Collier of Siren Bikes. Here’s Brendan and his latest creation, the Siren “Song”. It’s Brendan’s take on a soft tail design with a twist. It’s a “69er” and he’s not relying on the aluminum stays for flex, as some other famous soft tail designs do.

Here’s what is flexing to get the estimated 2″ of travel from this design. It’s a titanium plate attached at both ends to the aluminum frame at the rear of the bottom bracket and the yoke between the chain stays. Brendan stressed that this is still in development and that he has plans to more cleanly integrate the plate into the frame structure.

Here’s another view of the plate and it’s design. Brendan expressed to me that he has several options to explore before he settles on a final design for the plate. In the meantime, this frame shown at Interbike is already being ridden by endurance athlete extraordinaire, Dave Harris. Dave will be using this for his assault on the 24 hours of Moab soon, so make sure to check out the results after the event to see how things went. You can also keep up with how the Siren Song prototype is doing at Dave Harris’ blog.

Brendan was pretty excited about this new project and described to me how the suspension should work. It has a proprietary shock by Cane Creek, specifically tuned to work with this design. Based on the AD series, the shock is set so it has a “preload” condition allowing the shock to be more active over smaller trail chatter. The shock is also very tunable, and should work for a variety of trail conditions and rider preferences. Cane Creek also offers different valving options that can further alter the way the rear end works for a rider.

Finally, I had to ask if Brendan planned on offering a full on 29″er version of this design in the future. The answer was a resounding yes. Brendan wants to first get the 69″er version in the can and then he’ll focus in on the 29″er version of the Siren Song sometime in early ’08.

I can’t wait to see how this bike works for Dave Harris and to see the 29″er version in the future. I think Brendan is on to something here, since soft tails and 29″ers seem like a great idea to me. Check out the future progress and Siren’s other bikes at their website.

A Scalpel 29″er? I have an anonymous source telling me that Cannondale is currently testing a 29 inch wheeled version of it’s Scalpel full suspension bike. The source said that plans are to bring this proven design and technology to the 29″er realm but not until the ’09 season. Well, that’s a long wait but it leaves plenty of time to save your ducats!

Trek World This Weekend The Trek/Fisher/LeMond/Bontrager dealer only show is this weekend up in Madison, Wisconsin. Look for a full pictoral report along with any other tidbits that I can dredge up myself. We will be posting things like images of the Cobia, X-Cal, and Rig 29″ers for ’08 along with Trek’s “69er” line up. Stay tuned for that and more next week!

Below you’ll find the most info available and first real pictures of the 2008 Gary Fisher Superfly.

The bike is aimed at serious cross country racers that like their frames light and extremely stiff and is the lightest frame that Gary Fisher has ever produced (in both 26 inch and 29 inch platforms).

The frame is Co-Molded Monocoque Carbon and weighs in at just 1250 grams. That’s 2.75 pounds.

The bike pictured below is the RockShox Reba made custom for the G2 geometry with a 51mm offset and 100mm of travel, however the Superfly will be sold with the G2 Fox F80 RLC.

The pictures below were taken when Nat Ross showed up with his mechanic, Myron Billy, to pick up the Superfly and get it dialed in for racing the upcoming 24 Hour Nationals. So everything you see in the picture is not necessarily what you’ll see on the stock version, notably the paint job. The paint shown below matches the Fisher team colors. The stock will be more of a nude carbon fiber color.

There’s more info below captioned with some of the pictures so read it all to get all the info. Pay special attention to the last picture…

And as always, click to see the pictures bigger.

Nat’s bikes are getting prep’d by Trek’s Vance McCaw and Nat’s mechanic. His two race bikes are currently the new HiFi Pro 29er and the Superfly.

Brace between the stays on the non-driveside to resist any braking twisting forces.

Notice the shaped downtube… the underside of the downtube is flattened to improve stiffness and performance.

Notice the front end… the front junction is built up for increased front end stiffness. In addition, this area is proportionate to the frame size. The XL frame has a larger proportionate area than a SM frame because the larger XL rider needs that extra material and on the flipside, the smaller rider doesnât need that extra material and weight. End result is that the ride quality among frame sizes remains the same.

The seatmast cluster is a highly shaped affair that ties in the top tube to the seatstays to increase overall stiffness. And check out that rear wheel clearance on the Bontrager Dry X Tubeless Ready tires.

Asymmetric chainstays. Tall driveside chainstay. Wide non-driveside chainstay balances the drivetrain forces. Also worth noting: there is loads of clearance between the stays. 10mm on each side w/ a 2.5â? tire.

Recently I was given the opportunity to ride a Trek 69er on some off road trails. I also was priveliged to speak with a few elite level racers concerning the format of running a 29 inch front wheel/ 26 inch rear wheel bike. One of those people was Mountain Bike Hall of Fame member Travis Brown. Here’s my take so far on the “69er” idea based upon my experiences and conversations with Travis and other elite level racers. This is my current answer for the question, “What is the deal with those 69ers ?”

Hey, it is what it is. A 26 inch rear wheel we all have experienced before. No amount of “magic”, (read big front wheel and the belief that it somehow changes the rear wheel characteristics) is going to mask that. Just think about it for a minute.

The front wheel is a 29″er, no surprises there for guys accustomed to 29″ers. It is what it is.

I don’t see any mystery here with the 69er. When you pedal uphill, you have to grunt and manouver more because the 26 inch rear wheel just doesn’t grip like a 29″er. Sure, it accellerates a bit more easily, but, (and this is the thing 69er folks don’t talk about) it loses momentum more quickly as well. The 29″er rear wheel takes a bit more effort, but when you have better climbing traction and a momentum conserving, “flywheel” effect, you can learn to use that to your advantage on rollers and downhills where I feel the 29″er has a huge advantage.

Travis Brown told me, (as did a couple of other 69er advocates) that they like the 26 inch rear wheel because they can get shorter chainstays and have the rear wheel tucked underneath them more. I didn’t hear anything about weight, acceleration, or other purported 69er benefits. My conclusion is that racers, elite level racers, like their bikes to feel a certain way, regardless of the advantages/disadvantages in regards to the 29″er/26″er debate. It would be just too difficult for them to have to relearn a new platform.

They seem to be a little more flexible when it comes to front wheel size and since that bigger wheel is #1. more comfortable, #2 gives better control, and #3 doesn’t upset the overall physics of pedaling a bicycle for them, ( ie: years of training on a specific wheel size, learning it’s traits and tuning yourself to that) they seem to be okay with the 69″er. I am speaking purely from an elite racing standpoint, and that is what the Trek lineup of 69″ers is designed for, per Travis’ own words.

So, that leaves us “mere mortals” to determine if what they are using makes sense for our riding. My opinion is this: I’m not an elite racer and I don’t have thousands of hours of fine tuning at risk if I choose a completely different wheel platform. So I look at what enhances my trail experience best. The 69er isn’t it.

For me, it’s the full on 29″er. At least that’s my experience so far. I am in the works now trying to obtain a 69″er for testing, to A/B test against a 29″er on my trails to determine if my hypothesis is correct. I am quite confident that I will find a 26 inch rear wheeled bike to be just that. A 26 inch rear wheeled bike, regardless of front wheel size.

First off, while Gary Fisher can be attributed to pushing the big wheels into the spotlight and getting dealers on board, the statement “Gary Fisher came out with a radical new mountain bike with extra-large wheels” is not extremely accurate. Mountain bikes with 700cc wheels wasn’t anything brand new back in 2001 and, as we’ve mentioned before here, Diamondback released one way back in the early 90s.

From there, they mentioned four different bikes… three 29ers and the Trek 69er. For each 29er they had a long list of likes and zero dislikes. That alone is a little weird… every bike has some drawbacks. And then on the Trek 69er, part of their dislikes was “riders need to carry two different-sized spare tubes, tires and spokes.” Who carries extra tires on anything but the longest rides? And most riders would know they can use 26 inch tubes in 29 inch tires, so no real complaint there.

Anyways, I’m glad to see that 29ers are getting some good media coverage, I just wish it wasn’t done in such an obvious half-ass way.

The recent product launch of Trek’s new “69er” line up signals a major departure from what was expected by them. Many had guessed that Trek would jump into the 29″er market to reap even more of a growing market than they could with just the Fisher brand. Instead it seems that they have struck out on a maverick course.

To be sure, the bicycles are well done. The frames are high tech marvels of aluminum, forged under hydraulic pressure into multi shaped tubes. The graphics are subtle, the paint spot on. Even one of the models drive trains reflects modern tastes in it’s 1 X 9 configuration. The bikes are going to look great on dealers floors, no doubt about it.

However; these race level steeds are going to have an uphill battle right out of the box. Not only are they $1400.00 and up, but they are in a market segment that faces stiff competition from lots of traditional and big wheeled bikes. The traditional bikes; bikes that are “safe” in racers and consumers eyes and the 29″ers which have a growing number of curiosity seekers based upon years of grassroots growth and evangelism, for lack of a better term. The 69er concept enjoys none of these benefits in the eyes of the public.

Then you have the dealers, who have just barely gotten on board with the 29″er concept and are now asked to stock yet another type of mountain bike with another wheel format altogether. Getting the dealers on board will be a challenge. See Gary Fisher circa 2002 for a great example of how dealers have traditionally been slow to accept a new format in mountain bikes.

Finally, you are looking at a concept largely driven by one company that has a minimal existing support base and a huge lack of understanding by most of the mountain biking public. Not to mention the fact that history doesn’t paint a very bright picture for Trek, judging from the failed attempts of the past to bring mixed wheel formats to the mainstream. All one can say now is, “what if ?” What if Trek had introduced a 29″er? I’m guessing it would have been wildly successful right out of the box.

One of the most rewarding parts about writing about the bicycle industry is meeting folks that are passionate about bicycles and riding them. Two such people are behind what is Siren Bicycles, based out of Idyllwild, California. I caught up with Brendan and Mary Collier at the Sea Otter Classic and found out more about their company.

Siren Bicycles is also unique in several ways that are a bit different in this day and age. In talking with owner Brendan Collier, I was a bit surprised to find out that he also works at Intense Cycles. Normally a employer might frown on an employee that starts up a business that sells the same thing. However; Brendan tells me that this unique situation is mutually beneficial to both companies. “I take a lot of what I learn from Siren and implement it at Intense”. In turn Intense allows Brendan to do what he does at Siren too. It should be no wonder then that the material Brendan chooses to build with is aluminum. It’s also no surprise that Siren is definitely an American built frame, since Intense also does things in house as well.

Using aluminum, building in America, and doing custom work are all not unusual in themselves, but doing all three is a bit unusual. Brendan believes aluminum gets a bad rap. “So many people get the wrong idea about aluminum being harsh from mass produced frames.” Brendan says that with careful tube selection and design an aluminum frame can be every bit as comfortable as any other material used to construct a frame from. Brendan does much of the work like design, selection of tubes, cutting and mitering, jigging up, and initially tacking the frame up. Brendan wanted the best welding possible, so he found a 30 year veteran of aerospace welding and got him to lay down the final welding on his bikes. That’s not the only person that Brendan gets to help out. He also leans on his wife for a bit of help.

Mary Collier is credited by Brendan as the more creative, graphic design part of Siren. In fact, she came up with the name for the company and the logo as well. Not only did she do that, but she also races Brendan’s creations in 24hr and endurance races, coming in as the the third female overall in the recently run 24hrs of Old Pueblo. Mary also chooses Sirens “55” model as her weapon of choice. I asked her why she liked the “69er” format that the 55 model uses. She stated that the rear wheel could be tucked up underneath her using a shorter chainstay than a 29″er could. The wheel weight was also somewhat of an deciding issue too. Mary said that the benefits of having the 29″er front wheel are huge for her endurance racing. Rolling over the rough terrain more smoothly and keeping her from getting beat up. Overall, she really underlined the proportional feeling she gets when riding her 55. She also pointed out that since Brendan can dictate size specific tubing, the rear end of the bike was very comfortable while still being efficient as a race bike.

Brendan also pointed out that his designs are first and foremost race bikes, but since he can custom design the bike, several accommodations are possible. The other model that rounds out the Siren bikes line up is the Trauco, which is a 29″er. Brendan says the Trauco is currently his best selling model, but he also doesn’t rule out the possibility of a future addition to the two models. The current models are available in six sizes using size specific tubing for each size. Future refinements Brendan is looking at are a new sliding drop out design with a trick tensioner in conjunction with Ahrens Bicycles and other refinements in the frames of the 55 and the Trauco.

Brendan and Mary are super committed to the vision of Siren and riding bicycles. Brendan even told me, “I’m prepared to go down in flames, but I hope it doesn’t come to that.” If passion and determination are worth anything, I doubt Brendan and Mary have anything to worry about!